engleski

Comparison of geochemical data of river sediments influenced by industrial and agricultural runoff

One of the main challenges of the modern world is the degradation of water quality due to human activities. The continuous interaction between sediment and water regulates the adsorption- desorption behaviour and thus the bioavailability of pollutants in rivers. The aim of this study was to compare the granulometric and geochemical characteristics of river sediments at five sites of the karst Krka River, which are under different anthropogenic impact: Krka River source (KRS, reference site), Krka River influenced by municipal wastewater (KRK-MWW), tributaries impacted by industrial effluents (Orašnica (TOR) and Kosovčica (TKO)) and by agricultural runoff (Butišnica (TBU)). After sampling the river sediments in July of 2021, carbonate content, particle size distribution, mineral oils, total organic carbon (TOC) and concentrations of Al, As, Ba, Cd, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn were determined. Carbonate content ranged 22.8 (TOR) - 92.8% (KRK), while the predominant particle size fractions were sand and silt at all locations. The particle size distribution indicated multiple material sources for the studied sediments. The obtained characteristics of the sediments were typical for karst rivers, but some parameters indicated anthropogenic impact. Compared to the other sites, levels of mineral oils and common industrial metals were high (Al≥Fe>Zn>Mn>Ba) at TOR and TKO, while TOC was elevated at TKO and KRK. Geochemical data of sediment from the Krka River watercourse indicated more evidence for industrial impact than urban and agricultural. Since pollutants in the sediment from karst rivers can easily become bioavailable, strict protection plans and continuous monitoring of the Krka River are recommended.

metals ; mineral oils ; karst ; Krka River

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